Multi-DOF Micro-Macro Bilateral Controller Using Oblique Coordinate Control

This paper discusses the suppression of torque ripples in motor drives. Current ripples caused by pulse-width modulation with frequencies of 10-100 kHz can be reduced by using high-frequency switching. On the other hand, current ripples caused by dead-times with 6kth-order ripples of fundamental frequencies increase with the switching frequency. Therefore, there is a trade-off relationship between the two ripples. To compensate for dead-times, feedforward compensation is widely used. However, effective compensation cannot be achieved if the feedforward compensation values contain modeling errors. This paper therefore reveals that the robustness of the output torque against compensation errors can be improved by using multilevel inverters. The proposed method is validated through simulations and experimental results.

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“…Additionally, the practical voltage of multilevel inverters during dead-time can be represented as (8).…”

Section: Voltage Error Of Multilevel Invertersmentioning

confidence: 99%

“…Bilateral control is a teleoperation method that transfers environmental haptic information to an operator. In addition, micro-macro bilateral control (7) achieves the scaled motion of human skills (supported by experience and knowledge) by using scale gains; these controllers are constructed in oblique coordinates (8) .…”

Section: Introductionmentioning

confidence: 99%

Torque Ripple Suppression Method with Multilevel Inverter and Feedforward Dead-Time Compensation

2016

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“…However, the principle of virtual work is not valid for scaled bilateral control systems. Therefore, to simplify the design (34) , the forces are transformed by T, which is also utilized for the position transformation. The energy is not conserved before and after the transformation.…”

Section: Bilateral Control System For Different Configurationsmentioning

confidence: 99%

Bilateral Control Method Based on Transformation Matrix Relating Motion Features and Tool Coordinates

et al. 2013

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Conventional bilateral controllers have been designed on the basis of a tool coordinate system. However, from the viewpoint of versatility, a transformation technique based on physical features of an operator is advantageous. Therefore, this paper proposes a bilateral control technique that can be used to operate slave robots; the technique is based on motion features of an operator and facilitates intuitive operation. Here, motion features imply displacement ratios of joints. A coordinate transformation matrix containing the motion features of the operator is obtained by principal component analyses. The transformation matrix can be used to abstract the motion features, while other transformation matrices require symmetric motion or symmetric sensor placement. The validity of the proposed bilateral control method is experimentally verified. In an experiment, the proposed method is applied to a wearable robot hand and a forceps robot. A grasping motion extracted by the wearable robot hand is transmitted to the forceps robot on the basis of the obtained coordinate transformation matrix.

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“…In order to consider the response on the differential mode, the following equation is derived by subtracting (20) from (19) …”

Section: Disturbance Observer In Modal Spacementioning

confidence: 99%

Mode Switching Bilateral Control for Master-Slave Systems with Different Motion Areas

et al. 2013

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This paper proposes a mode switching bilateral control for the extension of motion areas. Conventionally, a bilateral control with a dynamical matrix has been used to achieve haptic transmission with different motion ranges between the master and slave systems. However, this approach still does not allow operators to enhance operability, especially when the slave system is in contact with environment. Taking the contact motion in the bilateral control into consideration, a basic bilateral control with an Hadamard matrix for the same motion areas is suitable for immediate and fine haptic transmission. To solve the contact motion problem, the proposed control structure switches the dynamical and the Hadamard matrices between free and contact motion. The characteristic of the proposed method is that the structure of the disturbance observer is applied to the modal space in order to solve the initial-value problem. With this method, smooth switching of the modal transformation matrix is achieved in both soft and hard environments. As a result, the operability of the different motion areas will be enhanced.

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Multi-DOF Micro-Macro Bilateral Controller Using Oblique Coordinate Control

Cited by 110 publications

References 36 publications

Torque Ripple Suppression Method with Multilevel Inverter and Feedforward Dead-Time Compensation

Torque Ripple Suppression Method with Multilevel Inverter and Feedforward Dead-Time Compensation

Bilateral Control Method Based on Transformation Matrix Relating Motion Features and Tool Coordinates

Mode Switching Bilateral Control for Master-Slave Systems with Different Motion Areas

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